MLB Star Power Index: Dodgers ace Hyun-Jin Ryu is trending down at the wrong time; Cardinals' Jack Flaherty is surging

Ryu might be grooving his changeups after topping 160 innings for the second time in his career

Welcome to the MLB Star Power Index -- a weekly temperature reading that tells us which players are owning the baseball conversation right now. While one's presence on this list is often a positive, it's not necessarily a good thing. It simply means that you're capturing the baseball world's attention for one reason or another. The players listed are in no particular order. 

Time was when Hyun-Jin Ryu of the Dodgers looked the unanimous choice for the NL Cy Young award. The 32-year-old lefty as recently as Aug. 11 boasted an ERA of 1.45, and following his start on June 16 he had 85 strikeouts against five walks (he also went the entire month of May without walking a batter). When a pitcher is dominating like that, MVP talk inevitably bubbles up. Just a handful of starts ago, Ryu was in line for of the one of the best seasons of his generation. 

However -- in a plot twist as shocking as the nude scene in "The Crying Game" -- Ryu has dropped off that pace to a worrisome extent. In keeping with sales seminal best practices, here's a visual aid to keep attendees engaged: 

2019 Time frame	GS	ERA	SO	BB
Ryu through Aug. 11	22	1.45	121	17
Ryu since Aug. 11	4	9.95	21	7

All right so the drop-off is pretty stark. Also in related matters, Ryu over that first span allowed 10 home runs in 22 starts; since then he's given five home runs in four starts. In his most recent outing, Ryu was knocked around by the Rockies in Dodger Stadium, and the Rockies on the road are one of the worst offenses in all of baseball. 

Fatigue is going to be obvious suspect. Ryu has topped 160 innings for the second time in his career and for the first time since his rookie MLB season of 2013. Given that Ryu pitched a total of 213 2/3 innings over his previous four seasons, perhaps his arm's gone dead. However, there hasn't been a notable loss of velocity during this stretch of struggles. 

Following his most recent start against the Rockies, Ryu denied feeling tired. However, his manager, Dave Roberts, said this: 

"It's just command," Roberts said. "His moneymaker is the changeup and even when there's contact, it's just a tick too high. He's going to figure it out. Fortunately, there's plenty of time to recalibrate before we get to the postseason."

Roberts is right. Ryu has grooved his changeup much more often in recent starts than he did when he was dominating all comers earlier this season. It's not dropping in the usual fashion, and batters are thumping it. The changeup is of course a feel pitch, and recapturing that feel is often easier said than done. As the skip says, Ryu has another three starts or so to sort this out before the playoffs drop. That's one of the key things to watch down the stretch insofar as the Dodgers are concerned. Their 2019 season will be considered a failure if they don't win the World Series, and getting Ryu and his changeup back to that earlier form will be central to those efforts. 

Jack Flaherty -- Big Jackie Thunder-Mustard, as he's known in these parts -- has been surging beyond expectations of late. He was recently named NL Pitcher of the Month for August, and that was before he twirled eight innings of shutout, one-hit ball against the Giants. It's also more than "just" dominance from August onward. Check out Flaherty's numbers since his July 7 start against those same Giants: 

11 GS, 70 1/3 IP, 0.90 ERA, 85 SO, 17 BB, .433 OPS against, 32.3 K%

Not coincidentally, the Cardinals surged over most of this span (they're 35-17 since the break) and have elbowed their way into first place in the NL Central. Since the break, only Justin Verlander has a higher WAR than Flaherty, among pitchers. 

Flaherty flashed ace results at times during his rookie season of 2018, and the former first-rounder has the stuff to match: a mid-90s fastball, hard slider, nasty change-of-pace curve, sinker, and very occasional changeup. In this, his age-23, though, it took him a while to find his level. Following a rough trip to the bump against the Mariners on July 2, Flaherty was lugging around an ERA of almost 5.00. 

One thing Flaherty has done to make this leap is change his approach against lefties. He's started using his curve less against the opposite side while ramping up usage of the slider. That shift doesn't explain everything, obviously, but it has helped in platoon-disadvantaged situations, which was a problem up until early July. 

No, Flaherty isn't going to continue running a sub-1.00 ERA over the larger sample, but he's looking every bit the ace of a first-place rotation. The Cardinals need that to continue if they're going to fend off the Cubs in the Central and make a respectable showing in October. 

Marcus Semien, underrated baseball-ist. The Athletics are very much contenders, but they dwell on MLB's rural route, which explains their relative lack of bandwidth. As well, established star Matt Chapman hogs a bit of that modest allotment, and that leaves Mr. Semien spoiling for attention. Or maybe he doesn't really care. Apathy is always to one's enduring credit. 

What we do know is that Semien is having a darned fine 2019. This season, he's got an OBP of .360 and a SLG of .498, and he's also racked up 68 extra-base hits and 282 total bases in 140 games. All of this comes from a plus-fielding shortstop, which in part accounts for Semien's impressive WAR of 5.9. As Ken Rosenthal of The Athletic wrote not long ago, Semien worked himself from defensive liability to defensive asset at the most challenging position on the diamond. That he's done that while also authoring a career year at the plate is something indeed. 

This scribe managed to do the right thing and give Semien a slice of the attention he deserves. I notice you're still sitting there, not talking about Marcus Semien and stuff.

Pablo Sandoval recently took what may have been the final plate appearance of his Giants career. Relive it via the embedded Curtis Mathes color television console below: 

Hey, that's a nice send-off, if this is indeed the end of the line for Sandoval in San Francisco. He's in his walk year, and he underwent Tommy John surgery on Wednesday (which means his pitching career may end with an ERA of 0.00 in two appearances). The Giants are likely to enter into a rebuilding pivot with Madison Bumgarner likely bound elsewhere, and that may mean Sandoval isn't in their plans. 

That we're even talking about Sandoval's plans in 2019 is a minor baseball miracle. A few years ago, Sandoval inked a $95 million contract with the Red Sox. From 2015-17, he played just 161 games for Boston and over that span rang up a total WAR of -2.1. Yes, that's a negative number. The Sox wound up releasing him with almost $50 million left on his deal, and that point it was assumed his career was over. 

But it wasn't. He latched on with his old Giants for 2017 stretch drive and then came back in 2018. Over the past two seasons, Sandoval -- in defiance of age and performance trends -- has been quite a useful player. For that reason, he may find an opportunity next season, assuming his recover from T.J. goes as hoped. His run with the Giants, though, is probably over. 

It's been a good run. He put up almost 20 career WAR with San Fran, finished in the top 10 of the NL MVP balloting once on their watch, and made the All-Star team twice. Sandoval was also a core member of three Giant title teams. Speaking of which: 

Insofar as San Fran is concerned, Panda may be going elsewhere, but Panda's not going anywhere. Know what I mean?